Messages in this thread | | | Date | Tue, 2 Dec 2014 11:55:53 -0500 | From | Tejun Heo <> | Subject | Re: [PATCH 3.10] cgroup: break infinite loop in __css_tryget() |
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Hello, Roman.
On Fri, Nov 28, 2014 at 07:47:54PM +0300, Roman Gushchin wrote: > If cgroup_destroy_locked() sets the css refcount to a negative value, > we get an infinite loop in __css_tryget(). > > In this case css_refcnt() returns modified (non-negative value), so > both (t == v) and (t < 0) conditions are always false.
I don't follow. The count is biased and modified by unbiasing iff the value is negative. Here, @v is the unbiased value and @t is the verbatim value. If @v is different from @t due to unbiasing, @t must be negative satisfying the second condition and returning NULL, no?
Thanks.
-- tejun
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